In the manufacture of metalarc lamps, it is necessary to properly orient the arc tube within a lamp envelope.
This has been done in the past by hand-crimping a single metal strap having a mount frame comprised of a pair of elongated rods attached thereto to the glass stem of the lamp. The strap was clinched at a single point about the glass stem and frames. In addition to being labor-intensive, this method was ineffective; the proper alignment of the frames about the glass stem was not always achieved. Another problem common to this earlier procedure was maintaining a small, compact configuration of the band around the glass stem, so that subsequent manufacturing processes could be accommodated. A further problem with the aforesaid procedure was its inability to maintain proper stem tolerances and hand crimping pressure. Stem breakage was a fairly common occurrence. Needless to say, the hand clinching of the strap about the lamp frames and glass stem was both costly and inefficient.